Inspection vehicle for a turbine disk

ABSTRACT

An inspection vehicle structured to inspect a portion of the turbine disk, preferably the blade attachment hubs, while the turbine disk is disposed within a turbine housing assembly is provided. A turbine disk is generally planar but includes a inner hub and an outer blade attachment hub. The inner hub is coupled to a shaft and the blade attachment hub provides a surface to which removable blades are attached. The area between the inner hub and outer blade attachment hub is substantially planar. The inner and blade attachment hubs are the “inspection areas” that the inspection vehicle is structured to inspect. The inspection vehicle travels over, and is magnetically coupled to, the planar surface between the two hubs.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a device for inspecting a turbine diskand, more specifically, to a device for inspecting a turbine disk insitu.

2. Related Art

Turbine disks used as part of a power generation system must beinspected for cracking and other defects as a part of normalmaintenance. Typically, such inspections are performed by ultrasonictransducers, eddy current probes, and similar devices. Traditionally,the inspection of turbine disks require the disk assembly to be removedfrom the turbine housing assembly. This is a time consuming, laborintensive, and expensive process. One improvement over this systemprovided for an ultrasonic transducer, or other inspection device, to bemounted on an elongated arm having a tip structured to fit betweenturbine disk assemblies. This inspection system does not allow for theturbine disk assembly to remain in the turbine housing assembly. Toprovide access to the turbine disks, the turbine disks had to be removedfrom the turbine housing assembly. The turbine disk assembly is thenplaced on, and rotated under, a generally stationary inspection device.

SUMMARY OF THE INVENTION

The disclosed and claimed concept provides for an inspection vehiclestructured to inspect a portion of the turbine disk, preferably theblade attachment hubs, while the turbine disk is disposed within aturbine housing assembly. A turbine disk is generally planar butincludes a inner hub and an outer blade attachment hub. The inner hub iscoupled to a shaft and the blade attachment hub provides a surface towhich removable blades are attached. The area between the inner hub andouter blade attachment hub is substantially planar. The inner and bladeattachment hubs are the “inspection areas” that the inspection vehicleis structured to inspect. The inspection vehicle travels over, and ismagnetically coupled to, a planar surface between the two hubs.

The inspection vehicle is substantially autonomous; being able to moveover the surface of the turbine disk with little, or no, input from auser. The inspection vehicle includes an elongated body structured tosupport a plurality of components, a magnetic coupling assembly coupledto the vehicle body and structured to movably couple the vehicle body tothe turbine disk, a drive assembly structured to move the vehicle bodyover the turbine disk, and an inspection assembly structured to inspectthe turbine disk hubs.

The magnetic coupling assembly is used to couple the inspection vehicleto the turbine disks in situ, i.e. in an operational position, whereinthe plane of the disks extends generally vertically. The drive assemblyincludes a plurality of wheels, preferably four, wherein each wheel bothsteers and is linked to a drive motor. The drive assembly furtherincludes a sensor and a control unit. The sensors, including ultrasonictransducers structured to detect the inner diameter location of theinner disk hub, encoders on the wheels structured to track distancetraveled, and a gravitational sensor, to provide data enabling theinspection vehicle to track its circumferential location in the turbinedisk. The drive assembly is further structured to drive the inspectionvehicle over the surface of the turbine disk with either little or nouser interaction. The inspection assembly is structured to support anultrasonic transducer for inspecting either of the turbine disk hubs. Inthis configuration, a single user may operate the inspection vehicle.

BRIEF DESCRIPTION OF THE DRAWINGS

A further understanding of the invention can be gained from thefollowing description of the preferred embodiments when read inconjunction with accompanying drawings in which:

FIG. 1 is a schematic view of a turbine assembly.

FIG. 2 is an isometric view of a turbine disk and inspection vehicle.

FIG. 3 an isometric view of an inspection vehicle without an inspectionassembly.

FIG. 4 is a bottom view of a inspection vehicle without an inspectionassembly.

FIG. 5 is an top view of an inspection vehicle with an inspectionassembly.

FIG. 6 is a detail cross-sectional view of a wheel assembly and bevelgear assembly.

FIG. 7 is an isometric view of a wheel.

FIG. 8 is a detail top view of a turning assembly.

FIG. 9 is a detail isometric view of the inspection assembly.

DESCRIPTION OF THE PREFERRED EMBODIMENT

As used herein, a turbine disk “in situ” means that the turbine disk isin its operating position within a turbine housing.

As used herein, “operatively engage” and when used in connection with agear, gear-like device, or an axle means that two or more elementscontact each other in such a manner that rotation of one element causesthe other element to rotate as well.

As used herein, a magnet “operatively spaced” from another elementcapable of magnetic attraction means that the two elements are so closeas to allow the magnet to be attracted to the other element with asufficient force so that, if the magnet is not restrained, the magnetwould move into contact with the other element.

As used herein, “coupled” means a link between two or more elements,whether direct or indirect, so long as a link occurs.

As used herein, “directly coupled” means that two elements are directlyin contact with each other.

As used herein, “fixedly coupled” or “fixed” means that two componentsare coupled so as to move as one while maintaining a constantorientation relative to each other. For example, a wheel with a “fixedaxle” means that the wheel and the axle move as one component. Thus, arotational force applied to the axle causes the wheel to rotate.

Directional designations, e.g. upper, lower, above, vertical,horizontal, are generally related to the views shown in the associatedfigures and are not limiting upon the claims.

As shown schematically in FIG. 1, a turbine assembly 10 includes ahousing 11 (shown schematically) a plurality of disks 12 coupled to ashaft 14. The shaft 14 of the turbine assembly 10 extends generallyhorizontally. Thus, the planar surfaces 16 of the turbine disks 12extend generally radially. Each turbine disk 12 includes a inner hub 15,a radial planar surface 16 on each side of the turbine disk 12 and aouter hub 18 (not shown in FIG. 1, shown in FIG. 2). The radial planarsurface 16 provides the surface over which an inspection vehicle 20 isstructured to travel, as shown in FIG. 2.

As shown in FIG. 1-5, the inspection vehicle 20 includes a body 22, amagnetic coupling assembly 24 (FIGS. 3 and 4), a motion assembly 26(FIG. 5), and an inspection assembly 28 (FIG. 5). As shown in FIG. 3-5,generally, the vehicle body 22 is structured to support a plurality ofcomponents such as, but not limited to, the magnetic coupling assembly24 (FIGS. 3 and 4), the motion assembly 26 (FIG. 5), and the inspectionassembly 28 (FIG. 5). The vehicle body 22 is, preferably, elongatedhaving a leading edge 27 and a trailing edge 29. Generally, the vehiclebody 22 moves toward the leading edge 27, however, the vehicle body 22may move in reverse toward the trailing edge 29, or, if the wheelassembly wheels 62 (discussed below) are oriented generally sideways tothe longitudinal axis of the vehicle body 22, the vehicle body 22 maymove sideways.

Generally, the magnetic coupling assembly 24 is coupled to the vehiclebody 22 and structured to movably couple the vehicle body 22 to theturbine disk 12 that is being inspected. It is understood that, unlessotherwise noted, the “turbine disk” hereinafter refers to the turbinedisk 12 that is being inspected. Also, the motion assembly 26 isstructured to move the vehicle body 22 over the turbine disk 12 and theinspection assembly 28 is structured to inspect the turbine disk innerhub 15 and blade attachment hub 18.

As noted above, the radial planar surface 16 (FIG. 2), extends generallyvertically when the turbine disk 12 is in situ. Thus, the inspectionvehicle 20 must be structured to travel over such a vertical surface.This is accomplished by the magnetic coupling assembly 24. The vehiclebody 22 has a wheel side 30, which is the side adjacent to the planarsurface 16. As used herein, directional terms and phrases related to thevehicle body 22 shall be independent of the vehicle body's 22 physicalorientation/direction. Instead, directional terms and phrases related tothe vehicle body 22 shall be phrased as if the vehicle body 22 is likean automobile traveling over a horizontal surface. Thus, for example,the vehicle body 22 “top” or “upper” side is that side which is furthestfrom the turbine disk 12. Accordingly, as the magnetic coupling assembly24 is disposed on the vehicle body wheel side 30, the magnetic couplingassembly 24 is disposed adjacent to the planar surface 16. The magneticcoupling assembly 24 includes a plurality of magnets 32 coupled to bodywheel side 30. As shown, there are six magnets 32 in the magneticcoupling assembly 24. There may be any number of magnets 32, however,depending upon the weight of the vehicle body 22 and the strength of themagnets 32. The magnets 32 are operatively spaced from the turbine disk12. It is noted that the turbine disk 12 includes ferrous metals towhich magnets are attracted. Further, the amplitude, i.e. strength, ofthe magnetic attachment force may be controlled by adjusting the spacingbetween the magnets 32 and the turbine disk 12. Thus, at least onemagnet in the plurality of magnets 32 is coupled to the vehicle body 22by an adjustable coupling device 40, such as, but not limited to anadjustment screw, whereby the spacing between the turbine disk 12 andthe at least one magnet 32 coupled to the body 22 by an adjustablecoupling device 40 may be altered.

As shown in FIG. 5, the motion assembly 26 includes a plurality of wheelassemblies 50, a plurality of wheel drive assemblies 52, and a pluralityof turning assemblies 54. Each wheel assembly 50 is a substantiallycontained unit having elements structured to rotate the wheel assembly50 relative to the vehicle body 22 (i.e. turn the wheel), and elementsstructured to rotate the wheel 62 about the wheel's axis (i.e. drive thewheel). That is, elements of both the wheel drive assemblies 52 and theturning assemblies 54 are incorporated into, or disposed within, eachwheel assembly 50.

There are at least three, and preferably four, wheel assemblies 50. Thewheel assemblies 50 are, in the preferred embodiment, disposed in agenerally rectangular pattern. Each wheel assembly 50 includes agenerally circular housing assembly 60 and a wheel 62 having a fixedaxle 63 (FIG. 7). That is, the axle 63 is fixed to the wheel assemblywheel 62 and rotates therewith. Each wheel assembly housing assembly 60is generally cylindrical. As shown in FIG. 6, each wheel assemblyhousing assembly 60 comprises a plurality of stacked toroid members 64.The specific nature of each toroid member 64 is not relevant to thisinvention other than to note that the toroid members 64 are structuredto support the elements of the wheel drive assemblies 52 and the turningassemblies 54. For example, one toroid member 64 is a bushing structuredto extend about the second bevel gear 84 to protect the second bevelgear 84 from contacting other elements of the wheel assembly housingassembly 60. It is noted, however, that the lowest (closest to theturbine disk 12) toroid member 65 includes a pair of openings 67disposed on opposite sides of the toroid member axis. The wheel axle 63is disposed within the openings 67. Thus, the axis of each wheelassembly wheel 62 is in a fixed orientation relative to the associatedwheel assembly housing assembly 60.

Each wheel assembly housing assembly 60 is oriented so that, when thevehicle body 22 is coupled to the turbine disk 12, each wheel assemblyhousing assembly 60 axis, and the axis for the toroid members 64,extends generally perpendicular to the surface of the turbine disk 12.Each wheel assembly housing assembly is rotatably coupled to the vehiclebody 22. Thus, in this configuration each wheel assembly housing 60 isstructured to rotate relative to the vehicle body 22. Further, as theorientation of each wheel axis is fixed relative to the wheel assemblyhousing assembly 60, rotation of the wheel assembly housing assembly 60causes the associated wheel assembly wheel 62 to turn relative to thevehicle body 22.

As shown in FIG. 5 and as discussed below, the inspection assembly 28(FIGS. 5 and 6) and the position control assembly 104 include ultrasonictransducers 108A, 108B. As such transducers are highly sensitive withregard to positioning, the wheels 62, shown in FIG. 7, must bestructured to have a substantially constant radius. That is, the eachwheel 62 must be rigid. At the same time, however, the wheels 62 mustprovide sufficient traction for the inspection vehicle 20 to travel overgenerally vertical surfaces. Thus, each wheel assembly wheel 62 includesan outer surface 66 having a rigid portion 68, extending about thecircumference of the outer surface 66, and a pliable portion 70,extending about the circumference of the outer surface 66. The rigidportion 68 is, preferably, steel. The pliable portion 70 is, preferably,rubber. More specifically, each wheel 62 preferably has a steel body 72defining a circumferential groove (not visible). A rubber insert 74 isdisposed within the groove. The rubber insert 74 is structured to have athickness substantially corresponding to the depth of the groove. Inthis configuration, the outer circumferential steel portion of the wheelbody 72 defining the groove and the outer surface of the insert 74 havethe substantially the same radius and both define the wheel outersurface 66. In operation, the steel portion of the wheel outer surface66 maintains the spacing of the vehicle body 22 from the turbine disk 12and the rubber portion of the wheel outer surface 66 provides traction.Finally, it is noted that the axis of each wheel 62 extends generallyperpendicular to the axis of the wheel assembly housing 60. That is,when assembled, the axis of each wheel 62 extends generally parallel tothe planar surface 16.

As shown in FIG. 5, the inspection vehicle 20 includes at least one, andpreferably two wheel drive assemblies 52; there may, however, be morewheel drive assemblies 52. In the preferred embodiment, there are twowheel drive assemblies 52 wherein each wheel drive assembly 52 providespower to two of the four wheel assemblies 50. Each wheel drive assembly52 includes a motor 80 having an elongated output shaft 81 and a bevelgear assembly 82 for each wheel assembly 50. Each wheel drive assemblymotor output shaft 81 extends across two wheel assemblies 50. In thepreferred embodiment, each wheel drive motor assembly 52 is disposedbetween a wheel assembly 50 adjacent the leading edge 27 and a wheelassembly 50 adjacent the trailing edge 29. In this configuration, thewheel drive assembly motor output shaft 81 extends generally parallel tothe longitudinal axis of the vehicle body 22. When the wheel driveassembly 52 is disposed between the wheel assembly 50 adjacent theleading edge 27 and a wheel assembly 50 adjacent the trailing edge 29,the wheel drive assembly motor output shaft 81 extends from two opposingsides of the wheel drive motor 80.

It is understood that the bevel gear assembly 82 for each wheel assembly50 is substantially similar and that each bevel gear assembly 82 iscoupled to, and powered by, a wheel drive assembly motor output shaft81. Accordingly, the following discussion will address a single bevelgear assembly 82 but it is understood that each wheel assembly 50 has anassociated bevel gear assembly 82. As shown in FIG. 6, each bevel gearassembly 82 includes a first bevel gear 83, a second bevel gear 84, athird bevel gear 85, and a fourth bevel gear 86. The second and thirdbevel gears 84, 85 each have a toroid collar 87, 89 extending from theback side of the associated bevel gear 84, 85 and about the axis of theassociated bevel gear 84, 85. The distal ends of the toroid collars 87,89 are coupled and the second and third bevel gears 84, 85 aremaintained in a fixed orientation to each other. Thus, the second andthird bevel gears 84, 85 form a bevel gear shaft 88 wherein the secondand third bevel gears 84, 85 are disposed at the distal ends of thebevel gear shaft 88. Preferably, each bevel gear is angled aboutforty-five degrees.

A wheel drive assembly motor output shaft 81 extends over each wheelassembly 50 at a location substantially near the axis of the wheelassembly 50. The first bevel gear 83 is fixed to the wheel driveassembly motor output shaft 81 and is positioned to engage the bevelgear shaft 88. The bevel gear shaft 88 longitudinal axis extendssubstantially along the wheel assembly housing assembly 60 axis. Thatis, the bevel gear shaft 88 extends, substantially, through the centerof the wheel assembly housing assembly toroid members 64. Preferably, atleast one wheel assembly housing assembly toroid member 64, such as, butnot limited to a bushing, has an inner diameter structured to contactand support the bevel gear shaft 88. That is, the at least one wheelassembly housing assembly toroid member 64, such as, but not limited toa bushing, is structured to position the bevel gear shaft 88substantially centrally within the wheel assembly 50. The fourth bevelgear 86 is fixed to the wheel axle 63.

The first bevel gear 83 engages the second bevel gear 84. The thirdbevel gear 85 engages the fourth bevel gear 86. In this configuration,each bevel gear assembly 82 is structured to convert the motion of thewheel drive assembly motor output shaft 81 from a horizontal rotation,to a vertical rotation, and back to a horizontal rotation. Accordingly,the wheel drive assembly 52 is structured to cause an associated wheelassembly wheel 62 to rotate. That is, when the wheel drive assemblymotor 80 is actuated the wheel drive assembly motor output shaft 81rotates. Rotation of the wheel drive assembly motor output shaft 81causes the first bevel gear 83 to rotate. As the first bevel gear 83engages the second bevel gear 84, the second bevel gear 84 rotates aswell. As the second and third bevel gears 84, 85 are in a fixedorientation on the bevel gear shaft 88, rotation of the second bevelgear 84 causes the third bevel gear 85 to rotate. As the third bevelgear 85 engages the fourth bevel gear 86, rotation of the third bevelgear 85 causes the fourth bevel gear 86 to rotate. As the fourth bevelgear 86 is fixed to the wheel assembly wheel axle 63, rotation of thefourth bevel gear 86 causes the wheel assembly wheel axle 63 to rotate.As the wheel assembly wheel axle 63 is fixed to the wheel assembly wheel62, rotation of the wheel assembly wheel axle 63 causes the wheelassembly wheel 62 to rotate. Thus, the bevel gear assembly 82operatively engages both the wheel drive assembly motor output shaft 81and an associated wheel 62.

Rotation of the wheel assemblies 50 relative to the vehicle body 22,i.e. turning, is accomplished by the turning assemblies 54 (FIG. 5). Aswith the wheel drive assemblies 52, there are preferably, two turningassemblies 54 for the four wheel assemblies 50. In the preferredembodiment, there is a turning assembly 54A that is structured to turnthe two wheel assemblies 50 adjacent the leading edge 27 and anotherturning assembly 54B that is structured to turn the two wheel assemblies50 adjacent the trailing edge 29. In this configuration, the two wheelassemblies 50 adjacent the leading edge 27 turn at the same time and thetwo wheel assemblies 50 adjacent the trailing edge 29 turn at the sametime. As shown in FIG. 8, each turning assembly 54A, 54B includes amotor 91 (FIG. 5) having an output shaft 92, a worm gear 94, a centralgear assembly 96, and an outer gear 98. The central gear assembly 96includes a first gear 97 and a second gear 99. The central gear assemblyfirst and second gears 97, 99 are each fixed to a central gear assemblyaxle 95. As such, the central gear assembly first and second gears 97,99 rotate together. The turning assembly central gear assembly firstgear 97 is structured to engage the worm gear 94. The turning assemblycentral gear assembly second gear 99 is structured to engage the turningassembly outer gear 98. When there are two adjacent wheel assemblies 50,as in the preferred embodiment, the turning assembly central gearassembly second gear 99 is structured to simultaneously engage bothturning assembly outer gears 98 on adjacent wheel assemblies 50. Theouter gear 98 is fixed to the wheel assembly housing assembly 60. Thatis, the outer gear 98, or more specifically the teeth of the outer gear98, extend about the outer surface of the wheel assembly housingassembly 60. As such, the outer gear 98 may be one of the toroid members64 that forms the wheel assembly housing assembly 60. Alternatively, theouter gear 98 may be fixed to the wheel assembly housing assembly 60.

As with the wheel drive assemblies 52, the turning assemblies 54 aresubstantially similar and only one will be described hereinafter. It isunderstood that the two turning assemblies 54 have substantially similarcomponents and operate in a substantially similar manner. The turningassembly motor 91 is coupled to the inspection vehicle body 22 with theturning assembly motor output shaft 92 extending generally parallel tothe longitudinal axis of the inspection vehicle body 22. The turningassembly motor output shaft 92 extends at least to a location adjacentthe turning assembly central gear assembly 96. The worm gear 94 is fixedto the turning assembly motor output shaft 92 adjacent to the turningassembly central first gear 97. Further, the worm gear 94 engages theturning assembly central gear first gear 97.

The turning assembly central gear assembly 96 is rotatably coupled tothe vehicle body 22 with an axis extending generally perpendicular tothe longitudinal axis of the inspection vehicle body 22 and, when theinspection vehicle is in use, extending in a plane generally parallel tothe planar surface 16. The turning assembly central second gear 99 isdisposed, generally, an equal distance between the wheel assemblies 50adjacent the leading edge 27 or wheel assemblies 50 adjacent thetrailing edge 29. Further, the turning assembly central second gear 99operatively engages the outer gear 98 that is fixed to the wheelassembly housing assembly 60. If there are two adjacent wheel assemblies50, then the turning assembly central second gear 99 engages the outergear 98 on both of the adjacent wheel assemblies 50. In thisconfiguration, rotation of the central gear 96 will cause the twoadjacent wheel assembly housing assemblies 60 to move, i.e. rotate inrelation to the vehicle body 22, in tandem. Moreover, when the wheelassembly housing assemblies 60 have generally the same diameter, whichthey preferably do, the rate of rotation of the wheel assembly housingassemblies 60 is substantially similar.

When assembled, the actuation of the turning assembly motor 91 causesthe turning assembly motor output shaft 92 to rotate. Rotation of theturning assembly motor output shaft 92 causes the worm gear 94 fixedthereto to rotate. Rotation of the worm gear 94 causes the central gearassembly first gear 97 to rotate. As noted above, the central gearassembly first and second gears 97, 99 rotate together. Rotation of thecentral gear assembly second gear 99 causes at least one, and in thepreferred embodiment two, outer gears 98 on the adjacent wheelassemblies 50 to rotate. As the outer gears 98 are fixed to the wheelassembly housing assemblies 60, and as the wheel assembly housingassemblies 60 are rotatably couple to the vehicle body 22, rotation ofthe outer gears 98 cause the wheel assembly housing assemblies 60 torotate relative to the vehicle body 22. Thus, the leading edge wheelassemblies 50 turn in conjunction with each other and the trailing edgewheel assemblies 50 turn in conjunction with each other. Finally, it isnoted that, when the worm rear 94 is stationary, the wheel assemblies 50are substantially prevented from rotating relative to the vehicle body22. That is, any force applied to the wheel assemblies by the wheeldrive assemblies 52 does not cause any substantial rotation of the wheelassemblies 50 relative to the vehicle body 22.

As shown in FIG. 3, the motion assembly 26 further includes a positioncontrol assembly 100 (shown schematically). The position controlassembly 100 is structured to track and control the movement of theinspection vehicle 20. Generally, the position control assembly 100includes an integrated circuit/computer control that executes a numberof routines and which receives data from a plurality oforientation/motion sensors. The routines control the wheel driveassemblies 52 and the turning assemblies 54. Thus, by receiving dataindicating orientation/motion and controlling the motion of the vehiclebody 22, as well as measuring the distance to the hubs 15, 18 asdiscussed below, the position of the inspection vehicle 20 relative to adisk 12 may be determined and tracked.

The position control assembly 100 includes a control unit 102, aplurality of encoder assemblies 104, a gravity sensing unit 106 (allshown schematically), and at least one positioning ultrasonic transducer108. The control unit 102 has at least one programmable logic circuit110, a memory device 112 and at least one routine 114 (all shownschematically). The at least one positioning ultrasonic transducer 108,preferably, includes two positioning ultrasonic transducers 108A, 108B.The two positioning ultrasonic transducers 108A, 108B are structured toproject an orientation signal toward the disk inner hub 15. Datarepresenting the positioning ultrasonic transducers signal 108A, 108B iscommunicated to the control unit 102. That is, the at least onepositioning ultrasonic transducer 108 is structured to provide data tothe control unit 102. The control unit 102, and more specifically, atleast one routine 114 that is executed on the at least one programmablelogic circuit 110, is structured to interpret the positioning ultrasonictransducers 108 signal to determine a distance between the inspectionvehicle 20 and the inner hub 15.

Further, the plurality of encoder assemblies 104 each have an encoderwheel 120 and a reader 122. Each encoder wheel 120 has a plurality ofindicia 121 thereon whereby rotation of the encoder wheel 120 may bemeasured. That is, each reader 122 is structured to detect the encoderwheel indicia 121 as it passes past the reader 122 and to produce asignal pulse for each encoder wheel indicia 121 that is detected by thereader 122. Each reader 122 is in electronic communication with thecontrol unit 102. Each wheel motor assembly output shaft 90 and turningmotor output shaft 92 has an associated encoder assembly 104, i.e. anencoder wheel 120 is fixed to the output shaft 90, structured todetermine the rotational displacement of the output shaft 90. As thecharacteristics of the motion assembly 26 components, such as, but notlimited to, the diameter of the shafts, wheels and gears and the gearratios, are known, the position of the inspection vehicle 20 relative toa known starting point may be determined.

The gravity sensing unit 106 is structure to detect orientation relativeto vertical and to produce a signal having data indicative of theorientation. The gravity sensing unit 106 is also in electroniccommunication with the control unit 102.

Thus, the control unit 102 is structured to receive data from the atleast one positioning ultrasonic transducer 108, the gravity sensingunit 916 signal and signal pulses from each reader 122. The at least oneroutine 114 is stored on the memory device 112 and is structured to beoperable on the programmable logic circuit 110. The at least one routine114 is structured to accept the data from the at least one positioningultrasonic transducer 108, the gravity sensing unit 106 signal, as wellas the signal pulses from each reader 122. Based on this data, theposition of the vehicle body 22 relative to the turbine disk 12 may betracked. Further, the at least one routine 114 preferably includes asecond routine structured to control each turning motor 91 and eachwheel motor assembly 77. Accordingly, the control unit 102 is structuredto track the position of the vehicle body 22 relative to the turbinedisk 12 and to drive the vehicle body 22. Thus, the inspection vehicle20 may be made to be substantially autonomous with respect topositioning. That is, the control unit 102 may move the inspectionvehicle 20 to any point on the planar surface 16, and, by ensuring thatthe inspection vehicle 20 does not inspect an area that has beeninspected before, the hubs 15 and 18 may be inspected. That is, the atleast one routine 114 may contain data representing a map of the planarsurface 16 and, by comparing tracking data to the map of the planarsurface 16, the inspection vehicle 20 may be guided so that it does notinspect an area that has been inspected before.

It is noted that there are preferably two positioning ultrasonictransducers 108 with one positioning ultrasonic transducer 108 disposedat the leading edge 27 and one positioning ultrasonic transducer 108disposed at the trailing edge 29. These positioning ultrasonictransducers 108A, 108B preferably operate in tandem with one positioningultrasonic transducer 108 indicating the leading edge 27 distancerelative to the inner diameter of the inner hub 15 and the otherpositioning ultrasonic transducer 108 indicating the trailing edge 29distance relative to the inner diameter of the inner hub 15, therebyproviding equal radial position of the lead edge 27 and trailing edge 29of inspection vehicle 20 relative to the inner diameter on the inner hub15. Further, and as the hub 15 is disposed generally laterally and“below” the inspection vehicle 20, the two positioning ultrasonictransducers 108A, 108B are structured to operate at an angle of betweenabout 0 degrees and 30 degrees to the plane of the planar surface 16,and more preferably about 15 degrees to the plane of the planar surface16. It is noted that as the position control assembly 100 collects andtracks positional data, and as the position control assembly 100 cancontrol the drive motors, there is no need for motion control data (asused herein: data related to speed and direction) to be provided to thecontrol unit 102 from an external source. Thus, there is also no needfor communication cables structured to provide data to an externalcontrol unit. The elimination of the need for these cables alsoeliminates the weight associated therewith, which in turn reduces theweight of the inspection vehicle 20. When the weight of the inspectionvehicle 20 is reduced, the inspection vehicle 20 may be supported byfewer and/or weaker magnets 32 in the magnetic coupling assembly 24.

The inspection assembly 28 is a structure used to support testingequipment and, more preferably, an ultrasonic transducer 190.Accordingly, the inspection assembly 28 includes a gimble frame assembly150 extending from vehicle body 22 and an inspection ultrasonictransducer 190, as shown in FIG. 5 and in detail in Figure. The gimbleframe assembly 150 has a plurality of rigid members 152 wherein therigid members 152 are rotatably coupled to each other so as to providethree axes of rotation. As shown, the gimble frame assembly 150 includesa mounting portion 154 and a gimble portion 156. The mounting portion154 includes a rotatable coupling 158 structured to couple the gimbleframe assembly 150 to the vehicle body 22. As the mounting portion 154helps to space the inspection ultrasonic transducer 190 from the vehiclebody 22, the mounting portion 154 is typically coupled to the edge ofthe vehicle body 22. Preferably, the axis of rotation for the rotatablecoupling 158 extends generally parallel to the edge of the vehicle body22 to which it is coupled. Further, the rotatable coupling 158 mayinclude a biasing device, typically a spring 160, structured to bias thegimble portion 156 to the planar surface 16. As shown in FIG. 5, amounting portion 154 is disposed on a lateral side of the vehicle body22. A mounting portion 154 having a greater elongation may also becoupled to the either the leading or trailing edges 27, 29 of thevehicle body 22, as shown in FIG. 2.

The gimble portion 156 preferably includes two U-shaped yokes, that is,a first and second yoke 162, 164. The first yoke 162 has an elongatedcross member 166 and two tines 168, the tines 168 extendingperpendicular to, and from the tips of, the cross member 166. The firstyoke tines 168 extend in the same direction and generally within thesame plane. Although structured to rotate, the plane of the first yoke162 is generally parallel to the planar surface 16. A first pivot rod170 is disposed at a medial location on the cross member 166 and alsoextends in a plane generally parallel to the planar surface 16. Thefirst pivot rod 170 is further coupled to the mounting portion 154. Thefirst pivot rod 170 provides one axis of rotation for the gimble frameassembly 150.

The second yoke 164 has an elongated cross member 172 and two tines 174,the tines 174 extending perpendicular to, and from the tips of, thecross member 172. The second yoke tines 174 extend in the same directionand generally within the same plane. Two second pivot rods 176A, 176Bcouple the first and second yokes 162, 164 together. More specifically,the first and second yokes 162, 164 are rotatably coupled at the distalends of the first yoke tines 168 and the second yoke tines 174. The axisof rotation for the second pivot rods 176A, 176B are aligned. The axisof rotation for the second pivot rods 176A, 176B extends generallyperpendicular to the axis of rotation for the first pivot rod 170 andgenerally parallel to the planar surface 16. The second pivot rods 176A,176B provide a second axis of rotation for the gimble frame assembly150.

An axle 180 is disposed at the medial portion of the second yoke 164 andextends generally perpendicular to the planar surface 16. The lower endof the axle 180 is coupled to the inspection ultrasonic transducer 190.The axle 180 provides the third axis of rotation for the gimble frameassembly 150. A gimble drive assembly 200 includes a motor 201 having anextended output shaft 202 with a worm gear 204 disposed thereon. Thegimble drive assembly motor output shaft 202 extends generally parallelto the second yoke cross member 172. The gimble drive assembly worm gear204 is disposed adjacent to the axle 180. The axle 180 may have a gear206 fixed thereto that is structured to operatively engage the gimblemotor worm gear 204. The gimble drive assembly motor 201 is structuredto be controlled by, and is in electronic communication with, thecontrol unit 102. Actuation of the gimble drive assembly motor 201causes the axle 180, and therefore the inspection ultrasonic transducer190 to rotate on the center of the inspection transducer.

The inspection ultrasonic transducer 190 is fixed, directly orindirectly, to the axle 180. The inspection ultrasonic transducer 190has a generally planar inspection face 192 that extends generallyparallel to the planar surface 16. It is noted that the rotatablecoupling spring 160, which is disposed at the interface between thevehicle body 22 and the gimble frame assembly 150, biases the inspectionultrasonic transducer inspection face 192 toward the planar surface 16,that is, toward the surface of the turbine disk 12.

While specific embodiments of the invention have been described indetail, it will be appreciated by those skilled in the art that variousmodifications and alternatives to those details could be developed inlight of the overall teachings of the disclosure. Accordingly, theparticular embodiments disclosed are meant to be illustrative only andnot limiting as to the scope of the invention which is to be given thebreath of the appended claims and any and all equivalents thereof.

1. An inspection vehicle structured to inspect a turbine disk while saidturbine disk is in situ, said inspection vehicle comprising: a bodystructured to support a plurality of components; a magnetic couplingassembly coupled to said body and structured to movably couple said bodyto said turbine disk; a drive assembly structured to move said body oversaid turbine disk; an inspection assembly structured to inspect saidturbine disk said drive assembly includes a plurality of wheelassemblies, a plurality of wheel motor assemblies, and a plurality ofturning assemblies; each said wheel assembly rotatably coupled to saidbody and having a housing, a wheel and a gear assembly; each turningassembly structured to rotate a wheel assembly housing relative to saidbody; each said gear assembly structured to rotate the associated wheel;each said wheel motor assembly includes an output shaft; each said wheelassembly gear assembly having a drive gear and a wheel gear; each saidgear assembly wheel gear coupled to an associated wheel whereby saidwheel rotates with said gear assembly wheel gear; each said gearassembly wheel gear operatively engaged to said gear assembly drivegear; each said gear assembly drive gear is fixed to one said wheelmotor output shaft; whereby each wheel acts as a drive wheel; said bodyhaving a leading edge and a trailing edge; said plurality of wheelassemblies includes four wheel assemblies, two wheel assemblies beingdisposed near said leading edge and two wheel assemblies disposed nearsaid trailing edge; each wheel assembly housing being generallycylindrical and having an outer gear structure, wherein when said bodyis coupled to said turbine disk, each said wheel assembly housing axisextending generally perpendicularly to the surface of said turbine disk;said plurality of turning assemblies includes two turning assemblies;each turning assembly includes a turning motor having an output shaft, aworm gear, and a central gear; one said central gear rotatably coupledto said body and disposed between, and in operational engagement with,said outer gear structure on both said leading edge wheel assemblies;the other said central gear rotatably coupled to said body and disposedbetween, and in operational engagement with, said outer gear structureon both said trailing edge wheel assemblies; and whereby said leadingedge wheel assemblies turn in conjunction with each other and saidtrailing edge wheel assemblies turn in conjunction with each other. 2.The inspection vehicle of claim 1 wherein: each said wheel assemblywheel includes an outer surface; and each said wheel outer diametersurface having a rigid portion extending about the circumference of saidouter surface and a pliable portion extending about the circumference ofsaid outer surface.
 3. The inspection vehicle of claim 2 wherein: eachsaid wheel assembly wheel having a body; each said wheel assembly wheelbody and outer surface rigid portion being steel; each said wheelassembly wheel outer surface pliable portion being rubber.
 4. Aninspection vehicle structured to inspect a turbine disk while saidturbine disk is in situ, said inspection vehicle comprising: a bodystructured to support a plurality of components; a magnetic couplingassembly coupled to said body and structured to movably couple said bodyto said turbine disk; a drive assembly structured to move said body oversaid turbine disk; an inspection assembly structured to inspect saidturbine disk; said drive assembly includes a plurality of wheelassemblies, a plurality of wheel motor assemblies, and a plurality ofturning assemblies; each said wheel assembly rotatably coupled to saidbody and having a housing, a wheel and a gear assembly; each turningassembly structured to rotate a wheel assembly housing relative to saidbody; each said gear assembly structured to rotate the associated wheel;said body having a leading edge and a trailing edge; said plurality ofwheel assemblies includes four wheel assemblies, two wheel assembliesbeing disposed near said leading edge and two wheel assemblies disposednear said trailing edge; each wheel assembly housing being generallycylindrical and having an outer gear structure, wherein when said bodyis coupled to said turbine disk, each said wheel assembly housing axisextending generally perpendicularly to the surface of said turbine; saidplurality of turning assemblies includes two turning assemblies; eachturning assembly includes a turning motor having an output shaft, a wormgear, and a central gear; one said central gear rotatably coupled tosaid body and disposed between, and in operational engagement with, saidouter gear structure on both said leading edge wheel assemblies; theother said central gear rotatably coupled to said body and disposedbetween, and in operational engagement with, said outer gear structureon both said trailing edge wheel assemblies; and whereby said leadingedge wheel assemblies turn in conjunction with each other and saidtrailing edge wheel assemblies turn in conjunction with each other. 5.The inspection vehicle of claim 4 wherein said disk includes an axiallyelevated hub, and wherein: said drive assembly includes a positioncontrol assembly, said position control assembly having a control unit,a plurality of encoder assemblies, a gravity sensing unit, and at leastone positioning ultrasonic transducer; said at least one positioningultrasonic transducer structured to project an orientation signal towardsaid disk hub, said at least one positioning ultrasonic transducerfurther structured to provide data to said control unit; said pluralityof encoder assemblies each having an encoder wheel and a reader, saidencoder wheel having a plurality of indicia thereon whereby rotation ofsaid encoder wheel may be measured, said reader structured to detectsaid encoder wheel indicia and to produce a signal pulse for eachencoder wheel indicia that is detected by said reader, each said readerin electronic communication with said control unit; each said wheelmotor assembly output shaft and turning motor output shaft having anassociated encoder assembly structured to determine the rotationaldisplacement of the output shaft; said gravity sensing unit structuredto detect orientation relative to vertical and to produce a signalhaving data indicative of orientation, said gravity sensing unit inelectronic communication with said control unit; said control unitstructured to receive data from said at least one positioning ultrasonictransducer, said gravity sensing unit signal and signal pulses from eachsaid reader; said control unit having at least one programmable logiccircuit, a memory device and at least one routine; and said routinestored in said memory and operable in said at least one programmablelogic circuit, said routine structured to accept said data from said atleast one positioning ultrasonic transducer, said gravity sensing unitsignal and signal pulses from each said reader, whereby the position ofthe body relative to said turbine disk may be tracked.
 6. The inspectionvehicle of claim 5 wherein said control unit includes at least a secondroutine, said second routine structured to control each turning motorand each wheel motor assembly.
 7. The inspection vehicle of claim 6wherein said control unit does not require any motion control data froman external source.
 8. The inspection vehicle of claim 5 wherein: saidat least one at least one positioning ultrasonic transducer includes afirst and a second positioning ultrasonic transducers; said firstpositioning ultrasonic transducer disposed at said body leading edge;and said second positioning ultrasonic transducer disposed at said bodytrailing edge.